Add-subtract register



July 81 1952 G. c. ELLERBECK v 2,602,585

ADD-'SUBTRACT REGISTER Original Filed May 5, 1948 12 lSheets-Sheet 1 July 8, 1952 G. c. ELLERBECK 2,602,585

ADD-SUBTRACT REGISTER lOriginal Filed May 3, 1948 12 Sheets-Sheet 2 FILE-EA mvENroR. GRANT ELLERBECK July 8, 1952 G. c. ELLERBECK 2,602,585

ADD-SUBTRACT REGISTER l2 Sheets-Sheet 5 Original Filed May 5, 1948 NVENTOR. GRANT C. ELLERBECK h rr. z. tw l, Q\ l l July 8 1952 G. c. ELLERBECK 2,602,585

ADD-SUBTRACT REGISTER original Filed May s, 1948 12 sheets-sheet 4 2hY V` I 4 185 V57 55 o 56 5s INVENToR.

GRANT ELLenecx July 8, 1952 G. c. ELLERBECK 2,602,585

ADD-SUBTRACT REGISTER Original Filed May 5, 1948 12 Sheets-Sheet 5 INVENTOR. GRAN C. Enc-Ruck 5y T July 8: 1952 v G. c.- ELLERBECK I 2,602,585

ADD-SUBTRACT REGISTER Original Filed May 3', 1948 12 Sheets-Sheet 6 vNVENTOR. GRANT C. ELLERBECK July 1952 G. c. ELLERBECK 2,502,585

ADD-sUBRACT REGISTER Original Fi-led May 5, 1948 12 Sheets-Sheet 'I IN VEN TOR.

GRANT C. ELLERBECK BY G. C. ELLERBECK ADD-SUBTRACT REGISTER July 8, 1952 l2 Sheets-Sheet 8 Original Filed May 3, 1948 INVENTOR. G'RANT C. ELLERBECK July 8, 1952 G. c. ELLERBECK 2,602,585

ADD-SUBTRACT REGISTER Original Filed May 5, 1948 12 Sheets-Sheet 9 FEE-lm@ INVENTOR. GRANT CLLERBECK TIIIE 'ILUIIUJL July 8, 1952 G. c. ELLERBECK' y 2,602,585

ADD-SUBTRACT REGISTER Original Filed May 5, 1948 l2 Sheets-Sheet 10 FICE- 31E INVENTOR. GRANT CELLERBECK FEE- ll July 8, 1952 G. c. ELLERBECK 2,602,585

ADD-SUBTRACT REGISTER Original Filed May 1948 12 Sheet's-Sheet ll INVENTOR. GRANT C. ELLERBECK BY ADD-SUBERACT REGISTER INVENTOIL GRANT C. ELLERBECK Patented July 8, 1952 ITED ,STATE S PAT EN T OFFICE .ADD SUBTRACT REGISTER Grant C.1'Ellerbcck,jSan Leandro, Califa'assignor .togFriden Calculating Machine Co., Inc., afcor.- u.poration-of California Original application May 3, 1948, Serial No.

1949, Serial No.1'02;832

.1 This .invention ,relates to .adding machines. ,This @application is ya division soif ...my application Serial No. 24,888, filed .May/.3. `1-9i8zwhich\is Va continuationin part fof my .now rabandoned :ap- ,plication Serial No. 1693,-'730,:iiled August A29, 11946 yand `entitled YAdding Machine.

'.One object ofthe invention is V-to provide la vnovel value selecting mechanism.

,Another .object vof the invention is cto 4provide -an f improved mechanism for entering 'fa selected `value in la register.

`Another jobject of :the invention :is Ato provide fa vcyclically .Operable l plural order :adding or the like machine including .an ,improvedmechanism effective for entering:arselected value .in a register `during only afpart ofa machine cycle, and tens ktransfer mechanism ifor y,effecting interorder transfers during-apart of Ia Acycle .in which lthe .value entering mechanism .is ineifective .Other objects of lthe Ainvention -will -become evident after the following disclosure.

LIn the drawings:

Figure 1 is aplan view of themachine.

Figures 2A, 2B and 12C together ,comprise :a `section taken on the .line '2--2 '-in yFigure 1, -while Figure .2D is av fragmentary .sectional -view *.showing the details o'f .the spiral type of differential mechanism.

Figure is a section taken .as-indicated-by'the line 3-.3 in Fig. 2A.

.Figure-4 isa section taken `asindicatedby the line 4--4 in Fig. 2A.v

Figure 5Y is a vertical .section taken vas indicated -by the line 5-5 in Fig. 1.

Figure 6 is a vertical section taken as indi- `Figures 10A Aand 10B together comprise a secrtionttaken'on the line lD-ID in Fig. 1.'

Figurell is agrear vView ofthe machine with the cover removed.

Figure 12 isaverti'cal'section taken as indi- 'cated yby the line IZ-HinFig. 1'1.

Figure 13'is aplanview with theparts broken yaway taken as indicated bythe line |3-l3 jin Fig. '12.

Figure 'i4-is a vertical "section taken Uas indicated by the line l4-l4 in Fig. '1.

Figure `15 is'a view-'takenias/indicated by the line |5-l5 in Fig. 112.

` Figure .16. is affragmentary section'takenas infr.

As Vshown in'Flgure 1, the machineisprovided with .a keyboard comprising :a .plurality of ordinally :arrangedrows of keys 2i. After ,the

value has l,been rseton the keyboardl 20 .it Ais -erifao longitudinallyLbeneath the shaf-t'30 so `as to .1re- 'strain thenutfa'gainst rotation while permitting Divided YAand this application Jul-)'22,

tered vadditively .by depressing .the .add bark :22,

:or :negatively @by `depressing vthe l.minus vbar 23. Positive totals ...are 'indicated `by 4numerals dappearing inthe :lowertrow of windows 24. Direct `negative totals fare indicated by .numerals .apxpearing `in :the .upper -row of windows 25.

l Registration :control mechanism .Referring toFigs. 2A and 7V2D. vAssociated with .each ordinal :row of -keysl is,-a.-sha'ft 13.0 `which in each cycle vis lrotated a differential amount lcorrespondingto thefkey 2l depressed. Thisis yleifeotedby .the following mechanism. 'Shaft .'30 y `has-a .threadedportionSl .on whichfis threaded sa nut.SZhaVinganannular groove .3.3 `.engaged ,by afork,3,4,on afmember.` mountedjfor ,sliding movementparallel to ,the axis :ofthe shaft .130. .The mit ,32-,is .providedaboutits outenperiphery with [a Vseries .of '.tee'th n2,6 .which are adapted to cooperate with fa stationary y,tooth 21 extending machine. VThe tooth .21,is ,o'f `suchlength asfnot to :engage between vthe lteethJZl when the nut 'is.in.its normal or rearmostgposition as 4shown in 'Fig."`2A.' Hence, thenutl 32 and the `shaft 30 are free .to rotate when the inter-ordertransfer `-mechanism `operates Vnear the end of 'the cycle Member '.35 has a rack 36 rigidly attached thereto which engagemagear 40 havinga pinion '(Fig. 4) of smaller diameter integral therewith engagingaixed rack 4I. The gear and pinion vare mounted forrotationon a stud 42 in a slide 43. .Slide '43,.has 1two 'pin .and vslot connections 44 with 'the member '35,-an'c1 a spring .45.is.at

tached'at its Vfront end zto a stud .46 .onthe slide 43, and at its rear end is :attached tothe ',pin 41 of the rear pinand .slot connection 44. Pin 41 `is'secured to the memberi35 so that 'the 'spring 45`^tends to movethe member'35 rforwardly, and

.the slide 43 rearwardly. A latch .'50 vmounted onthelpin 41 normallyxengages'an earil on `the .slide.43 preventing .movement o'f the slide v43and the member .235. In the full cycleposition all of .the members 35 `are .restrained from movement by a` bail 52,;securedto va shaft 5.3 whichy engages `slots ,5,4 'in the member 35.

When 4a numeralikey 2l v(ligffZA) ,is depressed ,it `releases .the .latch by .the 'following means. v.Eachkey-Zl (Fig. 4) hasaiugl whichfengages :a Abail 56 pivoted at 451. .bail vSliis common to all thefkeys 2|.intheordinal As. shown in Fig. .2A.the

,coumer-clockwise. .Any .member .;35 which has been unlatehedvismnow free" to move forwardly under thefinuenceof its spring45. The slide 43 will be moved forwardly but, at a slower! speed. The member 35 is the driving member because of the mechanical advantage it has in the rack and gear train over the slide 43.V 'vThe 'Y member 35 moves forwardly until one ofthe lugs A 6| on the slide 43 engages the stem of :the depressed key. The fork 34 has now moved the nut 32 a differential amount corresponding to the value of the key depressed: and has` caused',Y

the shaft 30 to be rotated a corresponding angular amount.

Axlinkf92 .is pivoted to the key 94 with the key stem 9|. Depression of either of the keys 22, 23 causes the link 92 to engage a pin 95.y onanarm 96 secured to a shaft 91. Shaft 91 is'urgedclockwise in Fig. 5, or counter-clockwise in Figi 10A- by a spring 98 attached to an arm 99 VVfsecuredtothe shaft 91. The shaft 91 (Fig. 7)

has anfarrn: provided with a pin |0| which engagesalever |024pivotally mounted at |03 and having an ear|04engaging the plunger |05 of a .,microgswitch: |06.- Closure of this switch starts However, during this part of the cycle the angular rotation of the shaft 30 is not registered.

-The remainder ofvthe'registration control mechanism corresponds to that described in the patent `to Friden 2,229,889 issued January 28, `1941, and comprises a square shaft B2 rigidly secured t'othe threaded 'shaft 30. Slidably"mount'ed -on the square Shaft 62 Vis a sleeve 63 vhaving a pair of bevel gears 84, y 65 integral therewith. These gears are normally in a neutral position with respectQto a bevel gear 6,6 (Fig. 2C) on the numeral wheel shaft -61 which has mounted at the upper end thereof a numeral wheel-58. All' of ".the bevel gears y64', 85 are. controlled byagate '18 secured toa shaft `1| suitably mounted in the j frameo'f thefmachinen By a means presently-to bedescribed,` the gate 1|!A is rocked clockwise to engage the bevel gears 64 with the'gears 06 for additive registration, and is rocked countere clockwise to engage'bevel gears 65 with the bevel gears 60 for negativez'registration. During the vforward movement of thefbai152 (Fig'.v2A) thel gate f'i's' in its neutral position'so thatjthe 'angular Amovement ofthe shaft 30 is not trans- "mitted .to the numeral wheel 68. At the end of the forward movement of the bail52 thegate 10 is moved to engage either the gears 6'4 or thev lge'ars 65' with the gears (i6 so that upon return 'movement of the'bail 52 any differentially displaced' members 35 are restored to their home position, causing angular rotation of the shaft 30 corresponding to the value of the numeral wheel depressed, which is registered in the numeral wheel 68. In the last part of the cycle, the bail 52 moves tothe bottom of the slot 54without causing' displacement of the member35, Vand then returns to the starting position shown. During thislast part of the cycle, the shaft. 12 is rotated. y This shaft is connected by bevel gears` 13 to shafts 14,' each of vwhich has two transfer teeth 15 thereonY Which'cooperate with transfergears 16 on eachpair of square shafts 62 in the manner' described in the aforementioned patent. As there explained, the transfer gears 16 ,are'moved -into operative relationship with their transfer teeth 15 by means of a transfer tooth 11 `(Fig. l5)

.on thenumeral wheel shaft 61 which rocks trans- Yfer levers 18 lwhenever the numeral wheel 68 passes from 0 to 9 or from 9 to 0. Each .transfer v'lever has an ear 80 (see also: Fig. 2C) whichengages a grooved collar' 8| (Fig. 2B) secured to the hub of the gear 16.l One flange 82 of the- "c'ollar 8| vis disposed in a grooved collar 83 on a pin )'84slidably mounted'in the frame. A bail .85f I 'n'ounted` onv a sleeve 88 rotatably mounted on the shaft 1| Yis rocked clockwise in Fig. 2B to restore'thepins 84 and thus gears v16.

Operation kcontrol mechanism l ,Referring to rigs. r5 and eine plus bar 22 is v'securedfto a vertically slidable key stem 90, and

#the minus bar '28 is'secured toj a vertically slid- |3| pivoted at `|32 on the frame.

the motor. Shaft 91 (Figs. 8 and 9) has an arm |01 which controls a. .pawl and ratchet clutch which at the right; end, has secured thereto a cam 22 having a pin |23 thereonrto which is pivot'eda-'link |24 which is pivoted to a crank |25 'onthe shaft 53 so that for each revolution of the shaft I2 I the shafty 53 is osoillated counter-clockwise' from the position shown into clockwise positionand then is returned counter-clockwise to the fullcycle position. The shaft 53 has secured thereto a bail 52` (Fig. 2A) as'previously described. j

When either of the keys 22, 23 is depressed the gate 10,(Fig'. 2B) is notpositioned. This is effected subseduently bypower. Key 22 has a pin |29 (Fig. 5) which engages a cam face |21 on 'a 'link |28 pivotally mounted Aat its front end on an arm |29, pivotally mounted at |30 on the frame.

The link |28 is pivoted atitsrear end on an arm Depression of key 22 causes rearward movement of the link |28 and moves the end |33 of a slot |34 in the link |28 into engagement with'a pin |35 on a bellcrank |31 secured to the shaft 1| (Fig. 2B) of the gate 10. A Depression ofthe key 22 also rocks the link 92 (Fig. 5) around the pin and slot connection 94 and a pin |38 in'the'flin'k 92 engages the tail' |39 of a` latch |40 rotatably mounted on the shaft 91. The latch |40 which normally engages a shoulder |4|v (Fig. 6).'on a slide |42, releases the slidefor upward'movement under the influence of a spring-urged bellcrrank |43 which is pivotally, connected` tothe upperend of the slide |42. ,This upward movement of the slidel |42 disposes the upper end thereof in front of an ear |44 lon the link |28 to maintain .thelink |28 inits rearwardly displaced position'. After. the bail 52 (Fig. 2A) has reached'the end of its forward stroke a cam;|45 (Figs. 5 and 6) rocks its follower |49 counter-clockwise on 'its pivot |41. A link |43` transmits the movement of the follower to a lever |58 rotatably mounted at |5| and connected at |52 to. averti-cally movable slide |53 having a pin |54 therein. Pin |54 engages the cam face |55 on the slide |28 and imparts Vfurther rearward movementto the link |28, which `movement causes'A clockwise rotation of the shaft 1| to engage'th'e'zy bevelgears for additive registration, as previously described. The shaft 1| is latched-in this position by a latch |56 which -cooperates with' an ear |51 on the bellcrank |31.

When the link I 28 lis moved rearwardly, va cam face |60 thereon rengages a pin i|6| on vthe bell- 4crank |43, `rocking the bellcrank |43 counter- :clockwisamoving;the;slide |42 downwardly where ,it is relatchediby ithe latch |40. As previously shaft |2| Vvby driver pins |81 which engage the slots'of the Geneva wheel |82.

At the conclusionoffthe cycle the gate 18 (Fig. 2B) `is restored :to its neutral position. A cam |22 (Fig. 8) at the Iend of its revolution engages afollower |101pivoted at |1 which has a pin |12 .thereon that engages the latch |58 and rotates it counter-clockwise' to .release the bellc'rank |31. lThe shaft 1| is 4then centralizedv (see Fig. 18A) by a conventional centralizer 4mechf-rnisni |13. In case the operator does not release the key. 22 .intime for the latch |40 to ,befree .tore-'engage the shoulder |4| gon the slide |42 when thelatter ris moveddownwardly ,by the actionof the cam :face |188, the pin |8| and the bellcrank |43, the slide v|112 will 4be Vmoved .downwardly againxnear lthe .end ofthe cycle by the action of: the cam |22 and :the cam Vfollower |18 acting "on 'the slide. |42 through la pin and slot connection. |14. By this timethe key`22 ,normally will have been released vso Vasto condition'thelatch |40 for re-engaging ythe slide |42 lwhen-the latch 'is inits lowerposin tion.

Minus registration isefiected by depressing`the 4key 23 (Fig. 5) `which has a pin |155 on-its key stem 'whichengages a cam face |16 on vthe link |28 and moves lthe link |28 forwardly to bring the rear face |11 (Fig. 6) of the slot -|34 into `engagementwith the `pin |35. YDepression of the key 23 also causes rocking .of fthe link592 aboutrits pivot 93 and the pin`|38 onthe flinkreleases the latch |40 which permits the Islide |42 to move upwardly behind the -ear |44 on the link |218.

By l'the mechanism `previously described, the cam vM55-(Fig. 5) causes-the pinl 54 to be moved downwardliv into engagementwith the cam Aface |18 on the slide |28, Ypositively rocking-the bellorank |=31 counter-clockwiseto move the bail shaft v1| to its subtractive position where itis held byv the latch |58. The A`cam `face v |88 -on' the link 128 (Fig. 6) engages the pin |8| to rock the bellcrank |43 counter-clockwiseas before.

The "transfer gears are restored-as previously described, by rockingthe'bail"85-'(Fig.*2B), which is `securedto the sleeve-88. Referring to Figsvl'l vand l2, the sleeve 88has secured theretoa-c'am follower `|82 which cooperates "with lthe cam |83 v secured tojone of theactuator shafts] 4.

Keyboard lock and release n Each row ofkeys is` provided` with'a conventional latchslide V|85 (Fig. 21A) which -is moved rearwardly by a cam |788 on the keystem, yand is vmovedforwardly to latching'position'by a spring eration a bail |89 is rocked clockwise -by its shaft |90 to move all of the latch slides |85 rearwardly -rto clear the keyboard. This is leffected as olylows. The shaft'53 (Figs. 2A and 1 4) has s ecuredthereto a cam |92 which has a follower V|93 (Fig, 14). The follower-|93 is: connected .by :a

ilink |84 whichconnects thefollower |93 toafpin on ,an arm |96 zrotatably vmounted on la stud l |91 vinthe frame ofthe machine. Alink |98 -connects the;pin"l95 -to an arm4 200 rotatably mounted jon-:the shaft |98 asshown-in Fig-'14.

-One arm'fof the bail-|89 is connected @by a link 20| to abellcrank 282 pivotally mounted 'onithe pin |91 and pivoted to-a 4depending portion 203 ofthe ylock bail |88. A spring 204urges bail |89 clockwise and through theplink -28|;urgesthe lock .bail |88 upwardly,l it also maintains -apin -205 on bellcrank 282 in Contact with arm :|98.

The operation of thesepartsis as follows. In the forepart of the cyclethe cam |92 rotates clockwise and the `link |94 ismoved forwardly, rocking the armv |98 counter-clockwise, bellcrank 202 follows, and the lock bail |88 Iis moved-upwardly. In the last' part of -the cycle thecam |92 rotates counter-clockwise Ybeyond the sposition shown, moving the arm |96 and the ybellcrank l282 clockwise -tozwithdrawf thejlockbail .,I 88

and throughthe 1inkf20l, rock the bail |89 counterclockwise to release'the latch slides |85.

y True `negdtrve Atotal l Anach numeral wheel es (Fig. '12) hasfsecured thereto a gear 2|0 meshing with the gear 2| :on a shaft 2|2 providedwith -a numeral A wheel 2|3.

The lnumerals .on the numeral 'wheels 68 and 2 I3 vare arranged the gsarne, but the wheelsirotate :in Oppositevdirections at lall times, andthe nuf meral wheel i2|3 is'adaptedto display the comis displayed through the upper rowqof r-windows 25. Windows 24 and 25are-in ashutterZ |5f(Figs. 1-1, l2 and 13). y:Whenan overdraft'occursgthis shutter is moved to the y'right'inFigl to display the numerals onrthe y'numeral -wheels 2|3T'and to mask the numerals on the numeralwheels 88, and a registration'of 1 isI effected inthe units secured to a shaft 2|8 `which has securedgthereto an Aarno 2|9 which isj connectedby a link22| `:to an arm 222 secured to a shaft 22.3.having a transfer lever 224 thereon which, is provided'wth'an ear 80 that engages a grooved collar 8| (Fig. 2B) attached to a transfer gear 18 on the square shaft 82 in the units order. A transfer tooth 15 is provided on the first actuator shaft 14 and is timed to engage its pinion 18 after transfer has been effected in the highest order so that whenever the highest order numeral wheel passes through the 9-0 position the registration of "1 is effected vin the units order. If the operation is negative and an overdraft-occurs the highest order numeral wheel will pass from 0 to 9 and this will cause operation ofthe device 15-18 to effect subtraction of "1 in the units order. When the overdraft is corrected by an ladditive operation, the highest order numeral wheel'will move from 9 to 0 and this will eect operation of the device 15-18 to cause 1'to be added in the units order.

".Ihefactuatortshaft 14 (Fig. Il) has ar'cam'225 7 thereon which, in the course of the transfer fphase raises a follower 226 which has a springpressed rod 221 attached thereto. Rotatably mounted on the rodv 221 is a coupling lever 228 which has a pin 229 constantly in engagement with aslot 230 (Fig. 13) in a plate 232. The upper end ofthe rod 221 has secured thereto an arm 235 provided with a pin 236 which normally engages in one of two holes 231. VThe plate 232V is rigidly attached to the shutter 2I5 so that the pin 236 engaging one of the holes 231 locks the shutter in its current position. When the cam 225 lifts the rod `221-it removes the lock pin 235 so that vtheplate 232 andthe shutter 2|5 are free to be adjusted. The front end of the lever 228 (Fig. A'12), has a pin 240 which is brought into engagementwith the tooth of a gear 24| on the numeral Wheel shaft 2|2 in the units order. This occurs during a transfer, and if an overdraft occurs the units order numeral wheelshaft'2l2 will be rotated one Yplace counter-clockwise. This is because the reversing gears 64, 65 are adjusted for subtraction, and when the added increment is entered inthe units order it will cause the numeral 'Wheel 68 to rotate clockwise as viewed from above, and, therefore, will rotate the gear 24| counterclockwise. This movement is transmitted through the pin 240, the lever 228 and the pin 229 to the plate 232 which is moved to the right, moving the shutter 2|5 to the right, Fig. 1. At the end l ofthe cycle, the lock pin 236 drops into the hole I23" to hold the shutter in position to display the true negative total inthe Windows 25. When the overdraft is corrected the numeral wheel 2 I3 Will receive an increment of -movement in the opposite direction, vthat is, clockwise, and through the mechanism just described, the shutter will be 'moved' to the left in Fig. 1 to again display the total standing in the numeral Wheels 68.

An'illustrative example of the above-described mechanism is given below, in which the numbers standing in the numeral wheels 68 appear in the left-hand column, vand those standing in the numeral wheels 213 areY in the right-hand column. The numerals displayed by the shutter are marked with an asterisk. The figure 5369 is registered 'in the numeral Wheels 68, 6,000 is set in the keyboard and is subtracted, this resulting in an overdraft and subtraction of 1 in the units order.

It also causes shifting of the shutter so that the true negative total 631 is displayed. The overdraft is then corrected by adding 2579 which causes the highest order numeral wheel v|38 to pass-from 9 to 0 and "1 is additively registered in the units order. The shutter again shifts, and "the new total, 19418, is displayed.

j 1.- In a calculating machine, a register comprising ordinally-arranged differentially rotatable means, means to provide a first series of indicating numerals in each order of said means, and means to provide a second series of indicating numerals in each order of said means, the numerals in said second series being the complements of the associated numerals in the rst series; shutter means normally disposed to display the rst series numerals and to mask the second series numerals but being adjutable to display said second series numerals and to mask said first series numerals; registration mechanism operable to cause additive or subtractive registration in said register; driving means for operating said registration mechanism; means responsive to an overdraft during additive registration for causing 1 to be added in the units order of said register by said registration mechanism; a normally ineffective coupling adapted to be rendered effective for operatively coupling said shutter means to said units order to thereby transmit movement from said units order to said shutter means, incident to entry of said 1 in said units order in consequence of an overdraft, and thereby to adjust said shutter means to display said second series numerals and mask said first series numerals; and means operable by said driving means for rendering said coupling effective.

2. In a calculating machine, a register comprising ordinally-arranged differentially rotatable means, means to provide a first series of indicating numerals in each order of said means, and means to provide a second series of indicating numerals in each order of said means, the numerals in said second series being the complements of the associated numerals in the first series; shutter means normally disposed to display the first series numerals and to mask the second series numerals but being adjustable to display said second series numerals and to mask said first series numerals; registration mechanism operable to cause additive or subtractive registration in said register; driving means for operating said registration mechanism; a device operable to cause l to be registered in the units order of said register by said registration mechanism, said device being rendered operable by passage of the highest order differentially rotatable means in said register through the 0 9 position indicated by the first series indicating numerals, the l being added in the units order if the registration is additive and being subtracted if the registration is subtractive; a normally ineffective coupling adapted to be rendered effective for operatively coupling said shutter means to said units order to thereby transmit movement from said units order to said shutter means incident to entry of said 1 in said units order by operation of said device and thereby to adjust said shutter means to display said second series numerals after an overdraft and to display said first series numerals upon correction of an overdraft; and means operable by said driving means for rendering said coupling effective.

3. In a calculating machine, a register comprising ordinally arranged differentially rotatable means, means to provide a first series of indicating numerals in Veach order of said rotatable means, and means to' provide a second series of indicating numerals in each order of said rotatable means, the numerals in said second series being the complements of the associated numerals inxsaid first series; differential value entering mechanism for entering selected values positively or negatively in said register; cyclically operable rotatable driving means; means operable during a relatively early part of a cycle of said driving means for operating said value entering mecha- 9k nism to effect entry of a` selected value in said register; tens transfer mechanism'for effecting tens transfer operations between adjacent. orders of said register; means operable-by` said 'driving mechanism during a laterpart'of said cycle for operating said tens transfer mechanism; a normally inoperable device adapted to be connected to said driving means to be operated thereby in'- dependently of entering a valu'ein4 the units order ofi` said register, by operation` of: said valueyent'ering mechanism, for entering a1 1 in said units order, said l being entered'v additively if' the preceding entry of the selected value in said relatively early part of said cycle was positive, and subtractively if the preceding entry of the selected value in said relatively early part of said cycle Was negative; means operable in response to passage of the highest order rotatable means through the 09 position for effecting connection of said device to said driving means during a still later ,v

quence of correction of an overdraft for movingY said shutter means from its adjusted position to its normal position.

4. In a calculating machine, a register comprising ordinally arranged differentially rotatable means, means to provide a first series of indicating numerals in each order of said rotatable means, and means to provide a second series of indicating numerals in each order of said rotatable means,

the numerals in said second series being the complements of the associated numerals in said first series; differential value entering mechanism for entering selected values positively or negatively in said register; cyclically operable rotatable driving means; means operable during a relatively early part of a cycle of said driving means for operating said value entering mechanism to effect entry of a selected value in said register; tens transfer mechanism for effecting tens transfer operations between adjacent orders of said register; means operable by said driving mechanism during a later part of said cycle for operating said tens transfer mechanism; a normally inoperable device adapted to be connected to said driving means to be operated thereby independently of entering a value in the units order of said register, by operation of said value entering mechanism, for entering a l in said units order, said 1 being entered additively if the preceding entry of the selected value in said relatively early part of said cycle was positive, and subtractively if the preceding entry of the selected value in said relatively early part of said cycle was negative; means operable in response to passage of the highest order rotatable means through the 0-9 position for effecting connection of said device to said `driving means during a still later part of said cycle; shutter means normally positioned to display said rst series of numerals and to mask said second series of numerals but being movable to an adjusted position to mask said first series of numerals and display said second series of numerals; means normally disconnected from said units order but being adapted to be connected drivingfmeans during said still `later partof said cycle and prior to the entry of said- 1in said units order for connecting saidgnormallydiscon-l nectedmeans to saidY units ordeny 5 Ina calculating machine, a, register com;- prisingordinally arranged differentiallyrotatable means, means to provide a first series of .indicating numerals in each, orderjof said rotatable means, and means to provide a second series of indicating numerals in each order of said rotatable means, the numerals in said second series being the complements of the associated numerals in said first series, differential-value entering mechanism for entering selected values positively or negatively in said register; cyclically operable rotatable driving means; means operable during a relatively early part of a cycle of said driving means for operating said value entering mechanism to effect entry of a selected value in said register; tens transfer mechanism for effecting tens transfer operation between adjacent orders cf said register; means operable by said driving mechanism during a later part of said cycle for operating said tens transfer mechanism; a rotatable toothed member operatively connected to the units order of said register during a still later part of said cycle; a toothed element rotatable by said driving means normally in a path displaced from said toothed member; means for effecting relative shifting of said toothed member and said toothed element to dispose said toothed member relatively in the path of rotation of said toothed element whereby said toothed member will be actuated by said toothed element and said units order will be operated to enter a 1 therein independently of entering of a selected value by operation of said .value entering mechanism; and means operable during said still later part of said cycle and in response to passage of the highest order rotatable means through the 0 9 position for operating said shifting means.

6. In a calculating machine, a register comprising ordinally arranged differentially rotatable means, means to provide a first series of indicating numerals in each order of said rotatable means, and means to provide a second series of indicating numerals in each order of said rotatable means, the numerals in said second series being the complements of the associated numerals in said first series; differential value entering mechanism for entering selected values positively or negatively in said register; driving means for operating said value entering mechanism; tens transfer mechanism for effecting tens transfer operations between adjacent orders of said register; a device operable independently of entering a value in the units order of said register by operation of said value entering mechanism for entering a 1 in said units order, said 1 being entered additively if the preceding entry of the selected value was positive and being entered subtractively if the preceding entry of said selected value was negative; means operable in response to passage of the highest order rotatable means through the fl-9 position for effecting operation of said device; shutter means normally disposed to display said rst series of numerals and to mask said second series of numerals but being movable to an adjusted position to mask said iirst series of numerals and display said second series of numerals; a gear rotatable with the units order rotatable' 5 means; a pin operatively connected to said shutter means and normally being disengaged from said gear but being movable into a tooth interspace thereof; and means operable by said driving means after the entry of said selected value in 10 said register and prior to the entry of said 1" in said units order for shifting said pin into said tooth interspace, whereby ensuing entry of said 1" in said units order will move said shutter means from one of its positions to the other of 15 its positions.

GRANT C. ELLERBECK.

12 Y REFERENCES CITED Thefollowing references are of record in the le of this patent:

UNITEDV STATES PATENTS Friden Oct. 30, 1945 

